#!/usr/bin/perl
# simple1.pl
use warnings;
use strict;

my @outer = (['a1', 'a2', 'a3'], ['b1', 'b2', 'b3'], ['c1', 'c2', 'c3']);

foreach my $outer_el (@outer) {
   foreach (@{$outer_el}) {
      print "$_\n";
   }
   print "\n";
}